Telephone system



May 15, 1928. 1,669,517

R. c. M. HASTINGS TELEPHONE SYSTEM Filed Sept. 28. 1923 10 Sheets-Sheet 1 Elam May 15, 1928.

Filed Sept. 28, 1925 I 2' 2' Maw 26 i'" i z 35 .7

l0 Sheets-Sheet 2 gjwuemtoz 7 May 15, 1928. 1,669,517

R. C. M. HASTINGS TELEPHONE SYSTEM Filed Sept. 28, 1923 10 Sheet,s-Sheet 3 May 15, 1928. 1,669,517

R. c. M. HASTINGS TELEPHONE SYSTEM v Filed Sept. 28, 1925 10 Sheets-Sheet 6 giwue ntoz May 15, 1928. 1,669,517

R. C. M. HASTINGS TELEPHONE SYSTEM Filed Sept. 28, 1923 10 sheets-sheet 7 alum/W244 May 15, 1928. 1,669,517

R. c. M. HASTINGS TELEPHONE SYSTEM May 155, 1928 1,669,517 R. c. M. HASTINGS TELEPHONE SYSTEM Filed Sept. 28, 1925 10 Sheets-Sheet May 15, 1928. 1,669,517

I R. C. M. HASTlNGS TELEPHONE SYSTEM Filed Sept. 28, 1923 10 Sheets-Sheet 10 Brig/202957 fE/u 2? MST/4'65; [ma/TR/x,

airman;

Patented May 15, 1928.

UNITED STATES P AT'E'NT RUBEN CHRISTOPHERMILLEB HAsTINos. DECEASED, Lara or COLUMBUS, 0310, BY ELIZABETH FULLER. H s'rINes, EXECUTE-IX, on .ooLU yiBUs, oniojiissioivon' TO THE INTERNATIONAL TELEBHONE COMPANY, OF COLUMBUS, OHIO, A oonnonanew or OHIO.

TELEPHONE SYSTEM.

Application .fi1edseptembe1228, 1923. Serial No. 665,378.

The invention relates to party-line telephone systems and apparatus ofrthe. kind comprising n'iagnetically operated selector disks at the substations, the rotation of wvhich disks is controlled by sending impulses ltrom the central: station. A purpose of the invention is to provide an improved system employing the present switchboard and line circuits with only the addition of a mechanical or master key selecting device. at the exchange, and with the. substitution.

at each substation of improved mechanism controlling the conditions of the substation instruments. It is also a purpose of the invention so to simplify the construction of the substation instruments that it will bev unnecessary to provide party-line subscribers with instructions as to the use of the telephones other than the instructions now customarily given.

The invention will bedescribed in connection with the accompanying drawingsand its novel features will-be pointedout 'in. .the appended claims.

In the drawings:

Fig.1 is a frontelevationofa substation.

controller set adapted for use ina wall telephone.

' Fig. Fig. 1;

is a section on the line '22 of Fig. 3 is a view similar toFig. 1, butshowe iiig some of the parts in section, and omitting some of the parts shown in Fig. 1.

Fig. l is a section on 'the l1ne.4.'l of Fig. 1.

Fig. 5 is a section on the line '5-5 of.

Fig. 1.

Fig. 6 a slde view o'f-thc selecting disk.

Figs. 7 and S are sections on the lines.

7-7- and 88 respectively of g- Figs. 9, 10 and 11 are diagrammatic views of the selecting (lISlItlIltl thecontacts thereby controlled, Fig. 9 showing the parts 111 normal condition, Fig. 10 showing'the parts in the position which they occupy whenthe receiver has not been replaced upon the hook, and Fig. 11 showing the parts in the position occupied when the receiver hook is Fig.-13;.is asimilaryiew showingthe parts In the positionassumed Whenthecal'led subscriber answers the call.

Fig. 14 is a view of the partsin the posihon-correspondingto Fig. 10.

Fig. 15 .is a: viewofthe partsinthe position of Fig. 11-, showing the travel of the pin which controlsthe contact blades in the calling substation.

F g. 16 is a similar view showing how thepartscomeintothe position of Fig. 10 when the calling subscriber fails to hang up the receiver onconipleting the call.

Fig. 17. is asimilar. View showing the travel of. the pin when the .operator at the exchange stat-ion notifies the, subscriberin order that he may hang up the receiver which he failed to hang up 'onthe, completion of the cell.

Fig. 18 illustrates a relay not shown in Figs. .1 and 3 but provided at the; substation {[0 control certain switch blades.

Fig. 1911s aplanvview of adeskte'lephone provided with controlling apparatus according tothe present-v invention.

FigQOisa section on line.20-,'-20 of Fig. 19.

Fig. 21is.a section on the .line 2121 of Fig. 19.

Fig. 22 isa section, with parts inelevation tlilrough the tubular support of a desk tele- P- F.1g.23.is a section. on the line 23-23 Figs. 24:. to .29 inclusive are diagrammatic viewscorresponding to the showings in Figs.

12.:to v17; inclusive..-

Figs. 30 andiSOtare respectively diagrammatic illustrations of; the circuits of. the calling .andanswering cords.

Fig- 30*.vis a. diagrammatic view ofi'he circuit of the wall vtelephone set illustrated inFigs. 1'to18.

Fig. .31 is a .diagraii'iinatic view of the substation circuit-used in conjunction with tliedesk telephoneot Figs. 19 to 29.

Before describing the construction of the substation instruments, a description willbe given of the various circuits involved in the use ot-thesystemf Calling the emchaage operator. j

Referring to .Figs-30 and 30*, on removal of the .receiveruR -the switch hook contacts l and 11 areclosed,as well as the contacts 11 and 129. Also the raising of the receiver hook swings the pivoted arm A-to .close contacts 15 and 16 and open thefcontacts 16 a nd 183 of the'call'up alarm. "This notifies the operator of the call by estab lishing the following circuit :-battery' B (negative side),conductor 1, line relay ;2, conductor 3, armature 4, contact 5, conductors 6, 7 and 8, junction 122, transmitter .9,

contacts 10 and 11, conductor 12, winding 13 ot induction 0011C, conductor 14, contacts 15 and 16,.conductors 17, 18 and 19, contact 20, armature 21, conductor 22, and ground 9 back tobattery. Energiaation of theline 1 relay 2 attracts armature 27, lighting the lamp throughthe circuit from battery B, conductor 24, lamp 25, conductor 26, armature 27, contact 28, conductor 29 and ground The central station operator is thus notifiedthat a subscriber desires a connection, an'dthe' answering plug P is inserted in ack J associated with thecircuit in which the lamp was lit. The insertion of the plug cuts out the lamp 25 and puts the operator in communication with the calling substation through the circuit from battery B conductor 30, relay 31, conductor 32, re-

From this point the circuit continues through conductors 36 and 37, relay 88, conductor lay 33, and sleeve contact of the plug.

39, and ground 9 back to battery. -This circuit simultaneouslyenergizes relays 31, 33

and 38. Energization of relay 38 opens the contacts '4 and 5 and 20 and 21, thus deen ergizing' relay 2,- whereby contacts 27, and 28 are opened and the lamp extlnguished.

. The main lines are now freeforselecting denser 57.

and ringing. l h

7 Preliminary selejctingimpctlse.

Relay 83 is quick acting and relay 31 is relatively slowin acting due to the provision of copper slugs, which may be adjusted to vary the energization period, which is preferably about one-fifth of a second Thus the. preliminary impulse period is in effect the period-from the instant of energization' of relay33' until complete energization of relay 31. impulse is from battery B conductor 40,

contact 41, armature 42 and conductor 43,

at the end 01" which current flow is divided,

one part of the circuit'continuing through conductor 44, contact 45, armature 46, con

ductor 47 and the tip contact48 of plug 1?. From the point of division the otherflpart of the circuit is to contact 49,armature 50, conductor 51, and ring contact 52 of the plug. From the plug tip 48, the circuit continues through contact 53, conductors 18, 17 and 54, relay 55,conductor 56 to con- At this time, the charge on the condenser is such that an impulse is drawn through relay 55 (by what is knownas con- The circuit for the preliminary denser kick) so that armature 62 is attracted and contacts 62 and 63 are closed, armature 68 being likewise attracted to close on contacts 67 and 69. Theclosing of contacts 62 and 63 includes'the relay55 in the circuit, through conductors 56 and 59," magnet 60 conductor 61, contacts 62 and 63, conductors 64 and 58, to ground. Current also flows from ring contact 52 to contacts 65, and conductorsj7, 8 -andi66to contact 67 and armature 68, where the line wires are short circuited. From this point, the circuit conrtinues to contact 69, conductor 70, relay71,

conductor 72,.conductor 59, steppingmagnet 60, conductor"61,contacts 62 Land 63,,con-

ductors 64 and 58 to ground g.- It will thus be seen that. the impulse sent over both line conductors in parallel. Relay 55 has too great a resistance to pass enough current change through a circuit from battery B,

conductor 73, winding 74 of relay 7 5, conductors 76, 77 and 78, contacts 79 and 80;

of the ringing key K, conductor 81, armature 82,.contact 83, conductor 84, contacts and 86 of theiselecting rkey .O v(here shown as a dial but which may be associated with a master and machine key such as shown in 7 Patent No. 1,588,108,.lune8, 1926, on application for patent filed by R. C. M. Hastings), conductor 87, contact 88, armature 50 (the relay33 being new fully energized) conductor 51, ring contact 52, line conductors 7 and 8, transmitter 9, contacts 10 and 11,

conductor 12, coil :13, conductor 14, contacts 15--16, conductors 17 and 18, contact 53,

jack tip 48, conductor "47, armature 46, con tact 89, conductor 90, contacts 91 and,

92, conductor 93, contacts 94 and 95, conductors 96, 97 and 98, winding 99, and conductor 100 back to battery. Energization of relay 75 prevents the supervisory lamp 210 from lighting by opening contacts 212 and 213. i V i i i i Opemtors listening-in "circuit.

ilhe operator now listens to the calling L, which places her receiver 108 on the line through the contacts 101 and 102, 103 and 104 of the key,conductor 105, winding 106 of the induction coil C, conductor 107, receiver 108, con-denser 110 and conductor 111., By

speaking into the transmitter 112, resistance 1n the translnltter c rcuit is varied, 'this circuit including battery, B conductor 113,

retarding coil 114, conductor 115, winding subscriber by throwing the listening key condenser being connected across the :battery armature 150 and conductor 151.

in parallel with winding 116and transmitter 112, by means of conductors 120 and 121. At the point 122 in the substation, the circuit is divided, one branch including transmitter 9, contacts 10, 11, conductor 12, winding 13, conductor 14, contacts 15, 16, conductor 17 conductor 18, while the other branch is from 122 through condenser I123, conductor 124, winding 125, conductor. 126,

receiver R, conductor 128, contacts 129 and 11, and conductor 12 back to the line 18. Calling substation.

Having learned the number of the .desired substation, the operator takes the calling cord (Fig. 30) and inserts the plugQP in the line jack of thedesired subscriber, and this produces a. preliminary step or impulse. The impulse circuit is from battery B, through conductor 180, relay. 131, conductor 132, relay 133, conductor 134 to-the plug sleeve 135. From this pointthe circuit is continued through conductors 36 and 37 associated with'the called/line, relayf 38, .conductors 39 and 22 to ground and. back to the'battery. The relays 131 and 138 correspondrespeetively with the rela-ys531 and33, providingan interval of about one-fifth of a second for the impulse. This impulse-is sent out 0VB1-'tl16 circuit from. battery B conductor '140,"contact 141, armature 142, and conductor 14?), to a, point where the circuit. is divided. One part continues through, conductor 144, contact armature 146,conductor 147, plug tip '148,cont t 53, and thence to. line-18 and, to thecalled substation asbefore described. LFrom'Jthe point olt' division theother part'o'l the circuit is through conductor149, armature .150,

.i conductor .151, ring contact 152, and con tact 65 toline 7 and'relay 71, as before described. I

After the lapse of the impulse interval, the relay 131 attracts its. armatures.andthe connections are ready for the operator to call the desired station. To dial or select the'operator throws the calling-key153,-closing the impulse circuit of the (119.1% or other impulse sending device. The circuit is from battery B, conductor. 154, contacts 155,156, and conductor 157 to the point Wherethe circuit is divided, one part going through conductor 158, contacts 159, 160, conductor 161, contact 145, armature 146, to the plug tip 148. The other part of the circuit is to thering contact 152, through conductor 162, contacts 163, 164, conductor 165, contact 166,

sired number of impulses thus sent out on the two sides of the line in parallel,

The destepping-the. disk D to. tl1e. clesi:1'e,d extent,

whereupon thev pin. 19 on. the. disk FD (Fig.

30"), at the wanted station on the. party line. which will hereinafter be described in.

detail, closes the contacts "167;, 168 of, the call-up alarm circuit. The, operator. then restores the calling key. 153.

Gall-up alarm.

The operator throws the ringing key 169,

whereby ."a circuit from the A, generator 170 .is established; as 't'ollowsa conductor 171,

contacts .172, 178, conductor 1714, armature .175 contacts 176 conductor 177 contacts 178, l64sot the restored calling key ;153, condoctor-165, contact 166, to plug r-ing152, conductors {7. and 8, condenser 123-, conductor 1:79,'bell 180, conductor 181, contacts 168,167,

conductor 182, contacts183 1,11Cl161it11df0011- ductor' 17 to the plug t1p.l4,8. From, this 1 point, the. circuit is completed to the. generator through 1.47, 146, 145, 16,1, 160, 1,84, 185, contacts 186,. 187 and conductor 188.,

Super vision.

.198, contacts. 199, 173 of the now restored ringing key 168, conductor 174, armature 175, contact176, conductor 1.77 contactsv 17 8, 164, E0 ring-contact. 152, through 'theitrans- "mitter and the .receiver, hook switch in the substation back to plug tip -14 8;and;ringing key/contact 11.89,, conductors 190 and 19 1, winding-192 and conductor 194 tobatter-ly.

'Ilhe armature 208 thus removed from contact 204 to extinguish the supervisory lamp 201, whose circuit includes in addition to the contacts rnentioned', battery B the conductors 200, .202 and 205, contact 206, -m'mature207 andeo nductor 208. VllQIL'tllB circuit includlngbattery B? isbroken in the. substation by the calleiil party hanging up,;the. deenergized relay 1 93 permits the circuit'of-thesupervisory lampto be closed.

The. supervisory lamp..210- of the answering-cord circuit-(Fig. 30) hereinbefore reterned'to, Which broken when the relay 75 is energized, similarly contains battery 5B), conductor-s 209, 211 and 214 and the.

contacts 212. andf213 through contact 215, 216, conductor 17 to ground. I

The-plug ot'the-calling-circuit is connected to the plug of the answering circuit by the conductors 2 18 and 220.,through condenser 219, andthe conductors 221 and through condenser 22 2: Both the, calllngaud. answering circuits include timing relays to ensure that .the relay 55in the substation mayhaye time to unlock before the establishment, of the ringing and talking circuits. In Fig. 30*, a battery B is in circuit with timing relay 224, conductors 225 and 226. WVhere the latter is connectedlto conductor 22?,the circuit is divided, one part beingthrough contacts 247,

248 and conductor249 to grounchwhile the nected to the following circuit :conductor 231, timing relay 232, conductor 233 to conductor 234, where the circuit is divided, one part being through contacts 250and 251, conductor to ground, while the other Y part is through conductor 2234, contact 235 and 236, conductors 237 and 205, and contacts 206 and 207 to ground. Thebreak occurs at contacts 175 and 176. The negative side of the-lineis opened only-duringthe selecting periods. i

In Fig. 30 the operatofis answering plug circuit includes an impulse sender, so that whenthe calling substation is connected with a substation on another line, the disks in all the substations on the line with the calling substations may be steppedto the zero position after completion of the call; Inipulses are-sent out from battery B through conductor 239, contacts 240 and 241, and conductor242 at the end of which the circuit divides. One part passes out on one sideoit' the line through conductor 243, and contacts 244 and 91to the plug tip 48, while the other part passes out on the other side of the line through conductor 245, and contacts 246 and 86 to ring contact 52. The circuit in the substation for actuating the stepping magnet 60 has already been described. 1

IS diUCtlL/'Of substation inatrimient. V Referring to Figs. 1 "to 18, a wall telephone comprises a support 1 to which isro movably attached'abase 2"provided with supporting standards 3. In the latter is mounted a shaft .4 having one end reduced at 4. and at its'other end carrying a'ratchet 5. The armature 6 of the stepping magnet (50 has attached to itand to the standard 3 a toggle 7 which is spring urged to pull the armatiire away from the magnet by a spring 8', assisted by a spring 11 whichis attached at one end to the standard' and atthe other to the operating pawl or detent which is reciprocatedby the armature to step the shaft. r 1

The disk D iscomposed of two plates 12 and 13 of different diameterswherebythe disk 18 provides an annular shoulder in which are formed guide ways 15and 16 and a notch 18. The disk may be adjusted on the shah; so that in the various substations on the line, the disks may have differing nor mal or zero positions. In the body of the disk are two apertures 13 and 14, and on the periphery of plate 12' is an inclined hump or projection 17, to enable the pinN,

as hereinafter described, to ride upwardly to 1 the level ofthe periphery of plate 13.

On the reduced end of the shaft is mounted a sliding sleeve or yoke 19 adapted to turn with the shaft, and urged to the left (Fig. 2) by a spring 20. .Pins 21" and .21 are pivoted tothe sleeve or yoke,an'd extend through the openings 13 and 14 in Said pins are connected to two enter the notch 18 when the sleeve is moved against the tension of the spring 20. The

switch provides a double pasageway into Ato which the central switch blade 16 at The pin N is carried by the arm A,

tached. and it cooperates with the periphery of the disk D tocontrol the contacts 15, 16 and 183..

A lever 26 pivoted at 27 to one of: the standards is adaptedto be swung when the receiver hook rises so as to move the sleeve against the tension of the spring. To this end, the-lever is engaged by a plunger 29, which is preferablyof insulating material provided-with a metal sleeve 30, and adapted to reciprocate in an opening in the standard to which the lever is pivoted. The outer end of the plungeris engaged by a roller 29 on'a pin 31, the latterbeing mounted in a link 31', The pin engagesthe hooked ends 10 of the contact spring 10, so that when the receiver is on the hook, the contacts 10,11

and 129' are separated as shown in Fig. 1.

The end of the link. oppositethe pin 31. is

"gaged by thehook 35 at the zeroposition when the relay '71 is energized. This relay is mounted as shown in Figs. land 4,

the hook 35 bcingsecured to its armature 34. The relay (Fig; 18) may be mountell):

pivoted to a short lever 32 attached to the ed in any convenient place, preferably the Y 1 bellbox of the wall set. In Fig. 18 the relay isshown as being carried by a bracket 37", and has only one armature 38, a lthoughfor conveniencein indicating thecir. cuits, this relay is shown in Fig. 30" as having two arinatures 68 and 62. In Fig. 18, the one armature performs the functions at the two armat-ures shown-in Fig. 30*, as i its arm 39 engages tl eglowermost contact 62 to close the cont-acts (Band 63, and-the contact 62' is connected with the contact (59 in such Way that contacts 67, G8 and'69 are brought together simultaneously with the closingof contacts 62 and 63.

The 'pivoted arm. A carries a projection 58' to %provide a luminous visual signal through an aperturein the casing of the in strument. This member may be coated with radiant paint, and when the arm A is moved to, one side of the disk to, indicate that one of the substations on the line is busy, as ind icatedin Fig, 10, a visual signal'of this condition will be given.

In Figs. 1 and 3, it eanbe seen that the Contact spring 167 of the call-up alarm circuit has a bowed end adjacent; the disk D so as to be engaged by the piup projecting from the disk in the axial'direction. In this way, the movement of the disk closes the contact blades 16 and 183 of the-call-u ii alarm circuit in the substation.

In F 19v to 29, ,a'modiiied form of the invention is shown, which is adapted for use in a desktelephone co nprisingthe usual tubular support 41 mounted on a circular base.

A lever 42 is pivoted in the support so as to be oscillated by movement ofthe receiver The lower end 43 of the lever projects into the base M", and engages against a lever 45 insuch manner that, when the receiver'hook is raised, the lever 123" permits the lever 45 to be actuated by a spring in such manner as to move a slidable plate 47" along the shaft l, U I

The periphery of the disk D in Figs. 19 to 29 is somewhat different from that ofthe disk in the embodiment above described. This disk is-provided with an annular shoulder but the grooves 48 areof suchdepth (Fig. 21) that the lower surface of the periphery of the disk corresponding tothe periphery of 12 in Figsrl to 18) is also grooved. -In thepresent embodiment, itis unnecessary to have the pins I extending throughthedisk and operating the levers supported by the disk and carrying the switch and shoe. Referring particularly to 4:5 ,llflS-tl forked end 46 carrying rollers which engage the slldable disk 47 which is V I spring urged awayi'roin the disk D Qn the shdable drskare mounted two arms 50' which enter the grooves 48, and have pro jections 51 of a height equal to the depth of the grooves in the annular shoulder. hen the disk'sti" is projected to carry the projections 51' into the notches as shown for instance in Fig. 28, the arms 50 are flus'h with the lower surface of the diskrwheihy the pin N on a pivoted arm contacting the contacts 167 and 168 may ride over thearm 50" as shown in Fig. 26.

Theclisk D has two normal positions and "tion raised. Figs. QOand' 21, it will be seen that the lever goes through two selective. cycles in a single complete revolution, "and for this reason it isprovided with two pins 52 corresponding to the single pin p of Figs. 1to1'18,'wliich .pinsqa-re adaptedsuccess vely to engagethe contacts 1G7and '168 of the call-up alarm circuit. In'consequence of'this modification of the. disk, its shaft 4" is provi-ded'witlr two diametrically opposite, radially extendmg arms 1 to 18 are preferablycoated with luminous paint so as to be visible in tlie'dark.

Referring now to Figs. 9 and 12, the pin it is shown in the position when the receiver is on the hook and the disk is in the normal or zero pos tion. When the receiver hook goes up, the switch -24 movesthe'pin n the calling station to the positio'n of Figs. 11

and 1 5, thus separating the ringing contacts 16 and183, and closing'the contacts and 16. When the operator plugs in, the disks in every substation on the'line are moved one step, as will be appreciated. In all the stations except that 'calling'the pin is switched by guidewayilyto"the position of Fig. 10, following the dash line course of Fig. 12 over plate 12. The talking contacts 15, 16 at thesestations eannot'therefore be closed and these stations'are shut out from the calling party line. Atthe calling station, the pin-is, throughout the revolution of the disk, onthe talking side thereof. as shown in Fig. 11 and by dash lines in Fig. 15. To ring the called stationthe exchange operator dia-ls its disk until the pin is in front of the shoe 25, atwhichljposition the pin closesrin'gi'ng contacts 167-and 168, the pin N'being shifted through'notch 18 when the receiver hook in the called stacuit at contacts 16, 183 and pfutsthe pin on the talking side ofthe disk. If, on completion of the call bot-h receivers are hung'up, and the disks n all thefsubstations of the line are stepped to'the'zeroposition, the pins N at the calling and 'calle'd'stations return to normal position by entering the inclined slots 16 and 'the guideway as "sl by dash l'l116S 'l .l Flg.:12. In all the 'sub stations not involved in the-call, thefp'ins N i remain in'the locked outposi'tion at HP 10, followingthefdash line course'of- Fig. 17.

This breaks the ringing cir- However, should the calling or called party-fai1 to"hang"up,fthe" pin will, when the disk gets to zero, }be in the position of Fig. 1.3. lnthis position, the subscriber iii cannotcall the exchange because the pin is behind the'switch point. But the ex change operator dials the disk until the pin 39 gets to the ringing position, the pin riding up on the humplT. The pin is spring mounted so that it caninove in a vertical direction until it is resting on shoe as shown iiiFigs. let and 16. Calling of'the subscriber directs his attention to the conditionof the receiverhook, on which he again hangs the receiver. Thisretracts the switch point 24, and the shoe 25" to the Fig. 12

position, so that: the pin? drops down in front of shoe- 25f- ."lhediskis theii stepped to zero where the pin N moves in front oi the switch 24: (see dashlines of Fig. 17

. ceive calls.

Normal conditions are thus restored (and the substation is preparedto make orre:

Referring now particularly to the desk set whose circuit is shownin Fig. 31, the norinal or zero position of the disk and pin is shown in Fig. 29, all the receivers being on their hooks. In this modification, it

is to be noted, the contacts 167 and 168' are 15, 16 and 188 of Fig,

l Vhen the receiver hook at the calling substation goes up, the contacts 10, 11 and 129 are closed and the partswassume the used in lieu of the several contacts 167, 168,

1 position of Fig. 28, theoperators signal lamp 25 being illuminated from battery 13, by .closing of the circuit of relay 2",- at 10 and 11 and at 167 and 168. This circuit, in the station, is from conductor 7, to conductor 75, primary of the induction coil, conductor 12 receiver hook contacts, trans initter 9, contacts 168 and 167- to the other side18 of the line. i

On plugging in to answer the call, the lamp 25 is entinguishedfin theinanner already described, by energization of. relay 38iroin battery B of Fig. 36", and the insertion of the plug in the jack sends out an impulse on the line in parallel, ashas been described, so that the disks 95in every substation on theline, including the calling substation, are all moved one step, by energization magnetfiil Froinfthe tip contact of the jack, the preliminary impulse] circuit is through conductors 18 and 75,

relayand conductor 73 to condenser 57".

Due to the charge on the condenser, the re- .lay energized,drawing up its armatures 63" and 68, whereby it closesa circuit for itself through.conductors 78 and 72?, magnet 60 conductor 61*, contacts 63' and 62 to conductor 77 and-ground. From the .sleeve contact 65 of the jack, the preliminary impulse circuitgoes out. on theother side of the line through conductors 7 and 74-? to contact: 69?? ,and armature. 68? ..Wl16l the} line wires are short circuited. f From this point the. circuit continues to contact 67, conductor 70, relay 71", stepping magnet 60, and conductor 61 to ground. The two branches of the circuit traversmg the stepping magnet in parallehit is energized so that the disks in all the substations ex cept that calling are moved one step along the dash line path of Fig. 24, wherebythe contacts 167 and 168 will remain open until closed by oneof the pins 52", the pin. N" being on the non-talking side oilthe' disk. In the calling station,-however, the one-step movement of the disk catches the pin N" on; the talking side of the disk, which Having ascertained the desired. station,

was. moved from the Fig. 28position, so that said pin retains the contacts 167 and 168( closed. i .80

the operator inserts her calling plug P in the proper jack, producing a preliminary inipulse which moves all the disks in the called line one step, as before described in connection with the calling line, thusprecluding the possibility of closing contacts 167' and 168' except by means of a pin 52, and she then dials until the disk I), of the desired substation has moved tar enoughto close con tacts 167 and .168 by means of pin '52.

The ringing key 169 is then thrown, closing the ringing circuit which, in the called substation is from line 7, conductor 75 bell coil, condenser 123*,trahsmitter 9, contacts 10 and 129, and receiver back to the winding. I When the conversation is completed and the calling and called parties both hang up their receivers, the projections 51 are retracted as indicated by dotted lines in Fig.

27, and as the operator stepsthe disks to zero, the pin iv in the calling substation rides against the outside or talking side of the disk until it enters" the slow 4-9. The reinaining movement of the disks to the zero position brings the groove 48 opposite tl c pin N, with the projection 51 in position to push out the pin the next time the receiver is removed from the hook. In the called substation the zeroizing of the disk brings the groove 48' opposite the pin, as shown by the light dash lines in Fig. 24. In all the other substations, also, the disks move from their preliminarily,once-stepped position to the zero position, the pins following the path of Fig. 29. p

Should, however, either or both parties to the call fail to hangup, zeroizing of the disk brings the pin N to aposition behind esbian the projection 51, the pinresting on top thearm hhwhose surfaceisflush with the lower surface of the diskD'C In this position, shown at the righthan'd sideoi Fig. 28,'thesubstation cannotcall the exchange. because the pin is prevented from being p'u'shed throi'igh the groove to the talking side. And even if the receiver should-v be hung up after-the disk is "zeroiz'e'd so'that the pinrests behind the projection, the substation will still be unable to call the exchange. However the central operator can call' the' thus locked out substation by dialing until a'pin 52, isbrought to the positioirwhere it closes contacts 167 and 168,

and when the conversation is completed and the receiver hung up, nor-11ml conditions will be" restored.

\Vhatis' claimed is 1. Ina sel'ectivesystem 'o-f party line telephony, the combination withfa" central station, a plurality of sub-stations electrically connected therewith, andsel'ecting means at the central station of a circuit controlling device at each sub-station, a telephone at each sub-station, a switch for each telephone controlled by a member of the tele hone, means at each substation under the sole mechanical control of a member of the telephone switch and cooperable mechanically with the circuit controlling device to place the sub-station in a talking circuit with the exchange station and means whereby the talking circuit may be made eflective atthe exchange station.

2. In a selective system of party line telephony, the combination with an exchange station and a plurality of substations con-- nected electrically, of a selecting device at the exchange station, a source of energy at the exchange station, a circuit controlling device at the substation, a transmitter, a receiver, and a receiver hook at the substation, means under the sole mechanical control of the receiver hook and cooperable mechanically with the circuit controlling device to place the substation in a talking circuit with the exchange station and means whereby the talking circuit may be made effective at the exchange station.

In a selective system of party line telephony, the combination with an exchange station and a plurality of substations connected electrically, of a selecting device at the exchange station, a source of energy at the exchange station, a circuit controlling device at the substation, a transmitter, a receiver, and a receiver hook at the substation. means under the sole mechanical control of the receiver hook and cooperable mechanically with the circuit controlling device to place the substation in a talking circuit with the exchange station, anda selected substation and means whereby the talking circuit may bemade eifecti v'e at the exchange the exchange station and means whereby the talking. circuit may bemade eifecti've'at the exchange station. k

5. In a selective system otp'arty line telephony the' combination with "an exchange station and a plurality of substations connected electrically, '01 a-selecting device at the exchangest-ation, a source ot'e'nerg at the exchange'station, a circuit "controlling device at the substation, a transmitter, a receiver, and a receiver *hook at the "substation, means under the "sole mechanical control of tliereceiverhook for signalling the exchange station and cooperable mechanically with the circuit controlling device to place the substation in talking circuit with the exchange station and a selected substation and means whereby the talking circuit may be made effective at the exchange station.

6. In a selective system of party line te lephony the combination with an exchange station and a plurality of substations connected electrically, of a selecting device at the exchange station, two sources of electrical energy and of different characteristics at the exchange station, a circuit controlling device at the exchange station, a receiver, a receiver hook and a call-up alarm at the substation, means controlled by the circuit controlling device for closing the call-up alarm through the operation of the selecting device, means under the sole me chanical control of the receiver hook and cooperating mechanically with the circuit controlling device to place the substation in talking circuit with the exchange station and for cutting out the call-up alarm and means whereby the talking circuit may be made eflective at the exchange station.

7. In a selective system of party line telephony the combination with an exchange station and a number of electrically con nected substations, of a selecting device and at least one source of energy at the exchange station, means at the exchange stat-ion for sending out selecting impulses in parallel on both sides of the line Connecting the ex change and substations, a connection be ti veen one side of theline and the ground at substation, a circuit for said magnet connected tobe traversed by the impulse sent out on the one side of the line, a relay in the circuit connection between one side of the line and the ground and adapted, on actuation, to connect the other side of the line with the magnet circuit, whereby said circuit is traversed by both impulses in parallel, a circuit controlling disk to be stepped by the magnet, a receiver and a receiver hook at the substation, talking contacts cooperating with the disk, and means controlled by the position of the receiver close the talking contacts in the calling substation.

8. In a selective system of party line telephony the combination with an exchange station and a plurality of substations connect-ed electrically, of a selecting device at the exchange station, a source of energy at the exchangestation, a receiver, and a, receiver hook atthe substation, a circuit controlling device at the substation, and including a stepby step mechanism having a disc with a plural diameter periphery, forming two guideways in communication with each station and a plurality of substations con- 1 nected,electrically, of a selecting device at the exchange station, a source of energy at the exchange station, a receiver, and a receiver hook at the substation, acircuit controlling device at the substation, and including a step by step mechanism having a disc .with aplural diameter periphery, forming hook to cooperate with the disk so as to two guideways in communication with each other, a switch for controlling-the con11nunieating point therebet-Ween, meansunder the control of thereceiver hook for moving said switch into and out of closing position and an electromechanical means for halting the step by step mechanism at normal position.

signature.

.50 In testimony whereof I haveaflixed my Eamon/Main of the Estate of Ruben Ohm'sto- V pher Miller H castings, Deceased. 

